New Study: ‘Summer temperatures were about 10°C warmer than today, even though the concentration of atmospheric CO2 was similar’

'Brigham-Grette et al. (p. 1421, published online 9 May) present data from Lake El’gygytgyn, in northeast Arctic Russia, that shows how climate varied between 3.6 and 2.2 million years ago, an important interval in the global cooling trend that accelerated rapidly at the end of the Miocene. Summer temperatures were about 10°C warmer than today, even though the concentration of atmospheric CO2 was similar.'